Sealing leading-in conductor



Apri1'6,19ze. Y 1,579,626

H. W. BANTA SEALING LEADING-IN CONDUCTORS Filed NOV. 19, 1923 byY www Patented Apr. 6, '1926.

UNITED STATES PATENT oFFlcE.

HENRY W. BANTA, OF NEWARK, NEW JERSEY, ASSIGNOR TO WESTERN ELECTRIC COMPANY, INCORPORATED, OIF` NEW YORK, N. Y., A CORPORATION OF NEW YORK.

SEALING LEADING-IN CONDUCTOR.

Application led November 19, 1923. Serial No. 675,486.

To all whom t may concern:

Be it-known that I, HENRY lV. BANTA, a citizen of vthe United States of America, residing at Newark, in the county of Essex '5 and State of New Jersey, have invented certain new and useful Improvements in Sealing.` Leading-In Conductors, of which the following is a full, clear, concise, and exact description.

This invention relates to evacuated glass vessels for electrical use and particularly to 4leading-in conductors for such apparatus.

An object of the invention is to provide a leading-in conductor of a form which may be easily applied to the vessel to form an enduring air-tight seal having a minimum liability to be destroyed by mechanical strains or by strains due to the differences in the expansion or contraction of the two materials forming the joint.

In accordance with one feature of this invention, the conductor used is of tubular perforate form, adapted to be securely embedded in the vessel by the glass thereof.

Another feature of this invention relates to the method of forming the seal which consists in general of inserting a slug or lump of the glass into the tubular perforate conductor and fusing the glass upon the outside and inside of the conductor to competely embed the same.

The drawings show one' embodiment of the invention.

Fig. 1 shows partly in section the braided wire withl the slug inserted.

Fig. 2 illustrates the method of forming the seal.

Fig. 3 shows the completedlseal.

Fig. 4 shows a pair of conductors Sealed into a vacuum tube. I

A hollow braided wire 5, preferably of the variety known as rat-tail, and formed of a metallic substance having a melting point higher than that of glass, is sealedv by heat over a slug of glass 6. The whole is then placed within a hollow glass tube 7, against -1 Which is directed a flame 8 which softens the tube so that it will fit closely about the wire-covered slug. Upon the application of further heat, the slugand the tube are melted together about the braiding of the wire, forming an airtight seal for the conductor. After the seal is formed, and, preferably, while the tube 7 is still hot, one end thereof may .be out away as shown -in Fig. 3.

The invention is peculiarly adapted for use in sealing leading-in conductors in vacuum tubes and the like, as shown in Fig. 4, in which a. conductor is used having a higher coeicient of expansion than the glass of the tube. In the usual form of such tubes, the conductor is formed in a single heavy strand which, because of its higher coefficient of expansion, presses, when heated, against the glass of the seal, tendin to crack the glass and destroy the seal. ll oreover, by making slight bends 9 in the plated conductor within the tube, all tendency of the wire to press against the seal can be completely avoided,

. as the expansion of the wire will then only cause an increase in the sharpness of the bends 9 which the flexibility of the wire readily permits.

What is claimed is:

1.' The method of sealing a tubular perforate member into a wall of ceramic material which consists in placing some of the material inside the member, surrounding the outside of the member with ceramic material, and fusing together the ceramic material inside and outside the member.

2. The method of forming seals for leading-in conductors in glass vessels for electrical use which consists informing a tubular, perforate conductor, placing a piece of glass within the tubularmember, surrounding the tubular member with glass and fusing together the glass upon the outside and the inside of the tubular member.

In witness whereof, I hereunto subscribe my name this 12th day of November, A. D. 1923.

. i HENRY W. BANTA. A' 

